Various types of fluid machines, for example, a compressor for compressing a gas or an expander for expanding a gas instead have been used. The fluid machines generate vibration due to a flow of the compressed or expanded gas.
For example, Patent Literature 1 proposes providing a straightening vane for controlling a swirl flow of a compressed fluid in a discharge pipe connecting a centrifugal compression mechanism and a work apparatus provided downstream. Patent Literature 1 describes that providing the straightening vane controls the swirl flow of the fluid, and reduces vibration in an entire flow rate region from a low flow rate region to a high flow rate region.